Finding Vampire Numbers

[peerreynders]

@sukhmeetsd

I am afraid if I did something wrong.

You are still running sequentially.

You are spawning a single process then entering a blocking receive and waiting for the result from that process. Only after the blocking receive is exited can the code advance and spawn the next process.

Now the BEAM can handle a million processes but given the circumstances it isn’t efficient.

Have a look at Task.Supervisor.async_stream/6. It allows you to constrain the number of tasks to the number of schedulers/cores to have the most efficient execution.

Proper use of Task.async?

A slightly more complicated example: # lib/my_app/application.ex defmodule MyApp.Application do use Application def start(_type, _args) do app = Application.get_application(__MODULE__) name = MyApp.TaskSupervisor children = [ {Task.Supervisor, name: name}, # use Task.Supervisor to protect {Worker, app: app, name: name} # Worker GenServer process from harm ] opts = [strategy: :rest_for_one, name: MyApp.Supervisor] Supervisor.start_link(children, opts) e…

Repeat previous pipe while condition?

Task.Supervisor is started as part of the application in MyApp.Application.start/2. It is then later used by Task.Supervisor.async_stream_nolink/6 within Worker.stream_tasks/2 Worker is simply a GenServer that needs results from multiple tasks - while being “safe” from them should they misbehave. async links to the spawning process so a crashing task will take down everything else. Worker.stream_fun is the function being run as a task. The input list [1000, -500, 2000] results in three separa…

https://medium.com/@dinojoaocosta/elixir-findings-asynchronous-task-streams-7f6336227ea